If the Japanese had planned an invation of Oahu after the bombing raid, do you think they could have pulled it off? I mean, there was nothing really stopping them, and it would have eliminated the Hawaiian islands as a threat. Plus, it would have given the Japanese use of it.

These are the men who gave us our world. The simple sounds of freedom we hear today are their voices speaking to us across the years.
-Bill Clinton, June 6, 1994

Originally posted by silentmidgetassasin: If the Japanese had planned an invation of Oahu after the bombing raid, do you think they could have pulled it off? I mean, there was nothing really stopping them, and it would have eliminated the Hawaiian islands as a threat. Plus, it would have given the Japanese use of it.

Except the two infantry divisions, a Marine regiment, a dozen or so independent artillery battalions, engineers, etc along with at least 1 Marine defense battalion (scheduled to go to Johnson atoll), not to mention heavy coastal defenses with guns up to 16" in size and, of course, the surviving nearly 200 aircraft (see Morison et al) and, most of the Pacific Fleet (yes, the battleships went down but not the cruisers, destroyers, submarines etc).As the largest amphibious operation of the war the Japanese launched consisted of just over two divisions it is unlikely they could have managed much more for an Hawaii operation. Given the defenses on Oahu and the other islands it is very unlikely they would have been successful. But, had they managed to take one or two islands (other than the heavily defended Oahu) they would have been in absolutely no position to hold it long term.

Besides, there were three aircraft carriers some where which could suddenly re-appear and cause some severe damage…

T.A.'s right. But I have to add that an invasion of the Hawaiian isles was also not possible because the difference of thinking between the Japanese Navy and Army High Command. The Army wanted to turn into China and finish actions there. The Navy realised that the US had to be isolated and put against the wall before attempting anything.

There were plans to invade Hawaii, but there was no co-operation between Army and Navy and as T.A. states, Hawaii was heavily defended.

"War is less costly than servitude, the choice is always between Verdun and Dachau." - Jean Dutourd, French veteran of both world wars

Originally posted by silentmidgetassasin: When the Japanese found out that the three American carriers weren't in Pearl, should they have turned around and waited until they were, or would that have been too costly and risky?

They couldn't do that for several reasons. First, their strike fleet was close to its limits on endurance. Fuelling at sea would have been a very risky and lengthy process. The Japanese were not as adept at this as modern navies often are. The equipment simply wasn't available to make it the fairly rapid evolution it is today.Second, the Japanese really had no way of knowing when the carriers might return or where they were. Their mid-Pacific and Western Pacific intelligence was limited to submarine sightings and the occasional long range patrol aircraft.Last, the longer they waited to launch their strike the greater the chance they could be discovered. The Japanese only had sketchy information on US patrol aircraft operations and couldn't rely on what they knew to ensure they were not in a routine patrol pattern. They also risked the possibility of a US Naval vessel or a commercial vessel blundering into their fleet.Thus, once they were committed to the final leg of the strike they had to launch as planned and hope for the best.

The Japs as well, I think, thought that the strike was a success and cancelled the third strike wave. Of course they were afraid as well that they might get caught but they sure thought that they had done their worst.Or what do you think T.A.?

Would Admiral Nugumo have to wait from Japan to change the plan[wait for the carriers]? As for invading Oahu ,it was,nt in their interest I thought.They only wanted to knock the US fleet out as so they would'nt interfere with their other conquests' and the embargo. Could be wrong though.

Originally posted by Kai-Petri: The Japs as well, I think, thought that the strike was a success and cancelled the third strike wave. Of course they were afraid as well that they might get caught but they sure thought that they had done their worst.Or what do you think T.A.?

There were several factors that resulted in Nagumo cancelling the third strike:* First, pilots returning from the first two strikes were estatic with the destruction they wrought. As was typical with Japanese pilots throughout the war they exaggerated their claims and their superiors bought those claims. Thus, Nagumo was presented a picture of Pearl Harbor being virtually destroyed.* Second, by the time a thrid strike could have been spotted and launched it would be quite late in the day before they returned. This could have presented problems.* Last, the escort destroyers were running low on fuel. If a thrid strike was to be launched the destroyers would have to be detached. The task force would then have to retire without their cover. With no knowledge of where the US carriers were this could have been a real problem for defense against a US air strike.

That's true, they just wanted to conquer asia, and the only thing standing in their way was the American Navy. I just thought they might have been able to easily take the island right after the air raid. But you're right, this was not in their best interest, and it would have diverted supplies and troops away from their primary objectives anyway.

These are the men who gave us our world. The simple sounds of freedom we hear today are their voices speaking to us across the years.
-Bill Clinton, June 6, 1994

However, in summer 1942 admiral Yamamoto had realised the problem American carriers meant. Therefore, destroying them at Midway, followed by an invasion of the island would have provided air based for the bombing of Hawaii and posibly, a base for further invasion.

"War is less costly than servitude, the choice is always between Verdun and Dachau." - Jean Dutourd, French veteran of both world wars

Originally posted by General der Infanterie Friedrich H: However, in summer 1942 admiral Yamamoto had realised the problem American carriers meant. Therefore, destroying them at Midway, followed by an invasion of the island would have provided air based for the bombing of Hawaii and posibly, a base for further invasion.

Midway was intended to draw out and finish the US carrier fleet. Yamamoto however, figured on only two US carriers. He thought the Yorktown would be out of commission far longer than it was (this is a sin of thinking your enemy does things the way you do....US shipyards were far more efficient than Japanese ones so the Yorktown was available). The Saratoga just missed being available too. She had been hit by a torpedo and was undergoing a major overhaul to remedy problems that sank the Lexington like replacing all the cast iron in the firemain system.But, a successful invasion of Midway bought the Japanese little. They couldn't effectively bomb Hawaii from there. The US in return could have just reached Midway with B-17 and B-24 bombers which unlike their Japanese counterparts some of which, like the G3M could reach Hawaii from Midway, would not require escorts to successfully attack. Second, supplying their forces there would be very difficult. Midway has a very small and difficult to negotiate harbor. There is no fresh water on the island. Japanese forces there would be pretty much on their own without hope of reinforcement if the US attempted to reinvade.The Aleutians operation was primarily a diversion and the forces landed were mostly withdrawn prior to the US retaking those islands. It was really just a waste of time and resources for Japan. But, the US did get a all-weather highway to Alaska out of it....

Originally posted by General der Infanterie Friedrich H: Besides, there were three aircraft carriers some where which could suddenly re-appear and cause some severe damage…

T.A.'s right. But I have to add that an invasion of the Hawaiian isles was also not possible because the difference of thinking between the Japanese Navy and Army High Command. The Army wanted to turn into China and finish actions there. The Navy realised that the US had to be isolated and put against the wall before attempting anything.

There were plans to invade Hawaii, but there was no co-operation between Army and Navy and as T.A. states, Hawaii was heavily defended.

I agree completely and thus the Japanese Army made the same mistake Hitler made in Europe..over-extension.

Just as Hitler should have finished off the UK before turning on Russia so should the Japanese have finished the Chinese.

It seems as though when you look through history many of the dictators in this world have always seemingly overextended themselves.

Just as Hitler should have finished off the UK before turning on Russia so should the Japanese have finished the Chinese.

Actually, the Japanese 'Blitzkrieg' in the Pacific was precisely meant for that. The breaking of the stalemate in China recquired much more logistical, technological and military power, and the cutting off of American help to China.

However, Japan didn't have the oil, rubber, iron, coal nor almost anything for doing an adequate build-up for the definite war-winning blow on China. Japanese strategy in winter 1941-1942 was to rapidly seize the territories rich in natural resources and raw materials —the East Dutch Indies for oil, Indochine for rubber, etc.— to expand its industrial base and isolate the United States, gaining enough time to decisively defeating China and then, from a stronger position, reach a stalemate with the US and maybe, peace terms.

At least they were closer and better at doing it than was Hitler in Europe.

"War is less costly than servitude, the choice is always between Verdun and Dachau." - Jean Dutourd, French veteran of both world wars

I think that had the Battle Fleet and Admiral Pye known that the Japanese were going to attack using a large carrier air strike he would have put to sea to avoid detection heading, most likely, south east away from Hawaii.
It was far more important for the fleet to remain intact than attempt to engage the Japanese immediately. If surface engagement was sought, it would have been the Scouting Force and carriers that would likely have been used.
Instead, the likely outcome would be a Japanese strike on a virtually empty Pearl Harbor followed by a US carrier ambush on their return voyage to Japan. After all, all three available US carriers were already at sea and at least two were capable of steaming to an intercept point.
As a historical note to this, at the time of Midway almost exactly 6 months after Pearl Harbor the Battle Fleet with 9 battleships was held in Hawaiian waters and not allowed to engage the Japanese in that battle. This is very indicative of what was likely at Pearl Harbor given 24 hours warning would have resulted in.

That sounds indeed like the most logical and best pattern to follow. But how would things have gone if an actual battle took place? Would the California and West Virginia would have suffered the fate of Repulse and Prince of Wales instead of just being severely damaged but ultimately put back into service as they actually were?

"War is less costly than servitude, the choice is always between Verdun and Dachau." - Jean Dutourd, French veteran of both world wars

Originally posted by General der Infanterie Friedrich H: Thanks for the input, T. A.

That sounds indeed like the most logical and best pattern to follow. But how would things have gone if an actual battle took place? Would the California and West Virginia would have suffered the fate of Repulse and Prince of Wales instead of just being severely damaged but ultimately put back into service as they actually were?

The Arizona, the newest of the battlewagons at Pearl Harbor on Dec 7th, had a paltry antiaircraft armament. The ship had a grand total of 8 5in./25 cal MK 11, single mounted guns, and 8 .50 cal machine guns. She had already had 2 of her secondary 5in/51 cal guns removed in anticipation of the installation of 1.1in anti-aircraft gun mounts. These had not yet been installed as of Dec 7th. The two heavy cruisers were a little better off. On average they had 8 5in/25 cal MK11 antiaircraft guns, 24 40mm in 6 quad mounts, 28 20mm single mount guns, and 8 .50 cal machine guns. The light cruisers (of which there were 6 at Pearl Harbor) had comparable armaments for anti-aircraft work. All told, I feel the Japanese naval air arm at that time would have caused just as much damage to the US force at sea as they did at Pearl Harbor with the added effect that these ships would have been forever lost in deep waters rather than the shallows of the harbor. If the remaining force had come within gun range The Japanese had two options; the first they could high tail it out of the area, after all the US battleships only had a top speed of 21 kts. The second option, fight it out there and given the US ability to fight surface battles even at Guadacanal, the Japanese would still have had a better than even chance given their torpedos and dedication to unit cohesion and harsh training conditions in the years prior to the war.

Originally posted by General der Infanterie Friedrich H: Thanks for the input, T. A.

That sounds indeed like the most logical and best pattern to follow. But how would things have gone if an actual battle took place? Would the California and West Virginia would have suffered the fate of Repulse and Prince of Wales instead of just being severely damaged but ultimately put back into service as they actually were?

Ok, let's assume the fleet comes under air attack at sea with something close to the original results. The likely outcome in that case is:

Arizona: Survives with one or two bomb hits and two torpedo hits that fail to rupture her torpedo bulkheads. She limps back to port. In full condition Zed, the bomb that caused the magazine explosion could not have done so so Arizona doesn't blow up.

West Virginia: Sunk after taking 7 torpedoes due to capsizing from massive damage. If the damage is spread over both sides instead she likely still sinks but only after a prolonged struggle to save her. Note in the original case her torpedo bulkheads were not penetrated.

Oklahoma: Sunk. Her insufficent stability and weak (comparatively) torpedo defense system does her in.

Nevada: Sunk. The bomb hit forward along with the torpedo hits allows massive flooding over the 3rd (damage control) deck that cannot be brought under control. There are just too many problems with her and Oklahoma due to their age.

California: Heavily damaged but remains afloat and returns to port under her own power. It was only the in port condition that allowed her sinking at PH to begin with.

Maryland: Damaged by bomb hits. Still mostly combat ready.

Tennessee: Damaged by bomb hits. Still mostly combat ready.

Pennslyvania: In dry dock. Does not participate.

The newest 4 BB's (Tennessee, Maryland, California and, W. Virginia) are far better protected than the PoW or Repulse were against torpedo attack. These ships had deeper, better designed defense systems than either British ship. Their internal subdivision, particularly their plants, were also better. They were better also in terms of shifting liquid ballast and in fire fighting equipment.Arizona was about equal to PoW in terms of torpedo protection, maybe just a bit worse. Nevada and Oklahoma were the oldest battleships at PH and suffered accordingly. Neither really was sufficently protected to stop a concentrated attack. But, both are still better than Repulse.The bombs the Japanese used were really, and accurately, crap. They showed little ability to penetrate armor and all of their damage was caused by initial penetration or hitting unarmored areas of the ships they struck.The only real advantage the British ships had was in AA fire power and the PoW had better deck protection. But, the latter matters little due to the poor performance of Japanese bombs.

Any idea how much the US would have to protect the oil tanks at Pearl Harbor? I read that with the oil gone the US fleet would have to put their base on the American continent so the Japs did a big favour by not hitting hard on those tanks??

Originally posted by Kai-Petri: Any idea how much the US would have to protect the oil tanks at Pearl Harbor? I read that with the oil gone the US fleet would have to put their base on the American continent so the Japs did a big favour by not hitting hard on those tanks??

It would have been a temporary problem at most. The US would have in short order replaced the tanks. The fuel problem would have been excerbated to some extent until this happened. However, the US had sufficent tankers in the Pacific that early war naval operations would not have been seriously impacted by the loss.This is in the same vein as suggesting destruction of the shops for ship repair. The US had two complete mobile advance bases virtually complete on the West coast in Dec 41. These were planned for use in the Western Pacific and were eventually sent there in 1944 (Ulithi Atoll). These bases were essentially complete movable shipyards that could do all but the heaviest ship repairs. One could simply have been moved to Pearl Harbor to cover until the permanent facilities there were repaired.Basically, the Japanese were hit right from the start versus the US. The US material advantage was literally overwhelming even in 1941.As I pointed out, less than 6 months after Pearl Harbor the US still had a battleline available that equaled or exceeded that of Japan's. This is even after the losses on December 7th.